Study on the suppression of lithium dendrites based on solid electrolyte Li7La3Zr2O12 with annealing treatment of Al interlayer

The lithium dendrites growth in Li 7 La 3 Zr 2 O 12 (LLZO) solid electrolytes has severely restricted the development of all-solid-state lithium batteries. Herein, two different dynamic properties interlayers of electronically conductive Al and an electronically non-conductive Al 2 O 3 are constructed at the Li/LLZO interface, and the lithium dendrite growth mechanism is explored. Results show that battery with Al interlayer occur internal short circuit in 95 cycles, while the battery with annealed Al 2 O 3 interlayer has good cycle stability of 1000 cycles with polarization voltage below 0.1 V. Besides, dendritic lithium dendrites can be clearly observed at the LLZO grain boundaries of battery with Al interlayer. Raman and XPS results show that the Al 2 O 3 interlayer reacts with Li + during the charge and discharge process to form a Li-Al-O compound which is Li + conductive. It is concluded that the lithium dendrite inhibition mechanism of the Li-Al-O compound interlayer is that it can promote the Li + conduction from LLZO to lithium anode to undergo a lithium deposition reaction, and prevents electrons from conducting to LLZO and combine with Li + to occur lithium dendrite growth. While for the Al interlayer, electrons can reach LLZO through the interlayer to combine with Li + thus occurring the lithium dendritic growth.